Coated fabric



May 24,- 1938. E. H. NoLLAU ET A1. 2,118,101

COATED FABRIC Filed April 2v, 1955 J'Woven Base fabric 5 -ubber Adhesive fC/gcu H Nol/au INVENTORS Dona/d A. Ran/fn ATTORNEY,

Patented May 24, 1938 UNITED STATES PATENT OFFICE COATED FABRIC Application April 27, 1935, serial No. 18,488

Claims.

This invention relates to adhesive backing and more particularly to non-soiling adhesive backing for medical and surgical use.

The general practice in the manufacture of 5 adhesive tape or medical plasters is to spread or apply in some suitable manner a suitably prepared adhesive mass on a woven fabric, the fabric usually being of a close construction, or on an unwov-en base material of a fibrous nature such as paper or material of a felt construction. Such material has the objection of having the adhesive coating stick to the uncoated face when the material is Wound in a roll as is the common practice in its use. A further objection is that the material when in use soils readily. Because of the nature of the surface which becomes soiled it cannot be readily cleaned and consequently becomes unsightly. It is therefore often necessary to replace it by fresh material but this is frequently not practical under certain surgical conditions. Further it is highly desirable to have the base to which the adhesive composition is applied waterproof or essentially so as this protects the adhesive composition from becoming softened by water or other liquids which may come into contact with thc back of the plaster or tape when in actual use. For these and other obvious reasons it is highly desirable to have a suitable material which is substantially waterproof and which will overcome the objections to the present type of material as noted above.

This invention has as an object the provision of a substantially waterproof backing material for adhesive tape or surgical plaster.

A further object is the provision of an essentially non-soiling backing material for adhesive tipe or surgical plaster.

Another object is the provision of a substantially Waterproof and non-soiling film for the base 4 of surgical plaster or adhesive tape which does not affect the adhcsiveness of the adhesive composition when in contact with the same. v

A still further object is the provision of a 45 waterproof, essentially non-soiling and washable adhesive tape or surgical plaster possessing properties which make its manufacture and use commercially and economically practical.

These objects are accomplished in the present 50 invention by applying to a Woven or non-woven base a suitable water repellent treatment and then applying to one face of the base a composition comprising cellulose nitrate and suitable softener which forms a substantially waterproof soil-resistant and washable film and applying to the opposite face a suitable pressure-sensitive adhesive composition.

The accompanying drawing shows diagrammaticallya vertical section of the finished product in which I represents a woven fabric as the 5 base material, 2 indicates a Waterproof, cellulose derivative coating, and 3 is a conventional pressure sensitive adhesive.

The invention is best illustrated by a description of a preferred embodiment but it is to be 10 understood that the invention ls not limited thereto except as defined in the appended claims.

A plain weave cotton fabric weighing approximately 3.78 ounces per linear yard inches wide and having a yarn count of Warp 80,'illler l5 80 which has been bleached i by any conventional method well known in the art of bleaching fabrics, is made water repellent by passing the fabric through a dye jig which contains a Water repellent composition. A composition which has been found to be particularly satisfactory contains about 75 gallons of water and about 25 lbs. of an emulsion of a wax in an aqueous solution of a salt of a carbohydrate amine polymer which is soluble in dilute aqueous organic acids, but insoluble in water as disclosed in United States of America Letters Patent No. 2,047,217 issued July 14, 1936 (about 96% water and about 4% emulsion).

.An example of such a compound is an aqueous 30 solution of an acetate of deacetylated chitin. The fabric is passed through three endsin the dye jig and the wet material dried in any suitable manner, preferably by passing through a tentering frame enclosed in a heated chamber, and kept 35 to a dry width of 40 inches. This water re, pellent treatment is applied to the fabric to retard wicking particularly on the edges on later exposure to moisture, water or other liquids. The fabric after being subjected to the above treat- 40 ment is quite water repellent whereas before the treatment it readily absorbs water in very much the same fashion as blotting paper. 'I'he fabric described above is known in the textile trade as Stevens cloth.

After the fabric is treated as above there is applied to one face thereof by means of a doctor knife a plurality of coats of a. composition comprising:

Parts by weight 5o 'The cellulose nitrate dispersion is prepared by dispersing 24 ounces of cellulose nitrate in one gallon of a solvent or dispersing medium comprising 40% ethyl acetate and 60% denatured ethyl alcohol. The cellulose nitrate used has a nitrogen content of 12.3-12.5% and a viscosity characteristic of between 100 and 150 seconds. The viscosity charactertisic is determined by noting the time of fall of a 1/4 inch steel ball thru a 10 inch column in a glass tube 1%" in diameter of a dispersion containing 16 ounces of cellulose nitrate in one gallon of a solvent or dispersing medium comprising ethyl acetate 40% and denatured ethyl alcohol 60%. y

The composition is applied as noted above in a plurality of coats suiiicient to deposit approximately 4 ounces per linear yard 39-inch width finished material. The material is sub- Ajected to a drying operation by passing over heated coils or through a suitably heated chamber or by other well known means, after the application of each coat. After the final coat has been applied and suitably dried the material issubjected to an embossing operation to emboss a suitable design on the surface as, for example, a skiver grain design.

To the uncoated side of the material thus prepared is applied by spreading a suitable quantity of a conventional pressure-sensitive adhesive rubber mass by any desired method of application'. The finished material is then cut into small sheets or strips which are later formed into rolls depending on the use to which the finished product is to be applied.

In applying the .waterproof and washable composition to the fabric which has previously been subjected to the water repellent treatment a precaution to be observed is to avoid having the composition penetrate the interstices of the fabric so as to come through on the opposite side. The composition is to be laid on the surface of the fabric rather pressed into the fabric. If it penetrates through to the back of the fabric diiliculty will later be experienced in uniformly spreading the pressure-sensitive adhesive rubber mass.

In the example of a preferred embodiment of the invention the fabric used was a plain or sheeting weave having a yarn count of warp 80, filler 80. used as for example felt or broadcloth fabrics, and many other fabrics, preferably although not necessarily, of a plain weave. fabrics such as pajama check may also be used. The proper choice of the fabric used Whether woven or non-woven will be determined largely by the use to which the material is to be applied and will be readily apparent to those skilled in the art. l

In place of the compositions for the water repellent treatment in the example, other compositions may be used which produce a similar effect. The application of various metallic soap treatments such as aluminum soap, various salt solutions such as aluminum acetate have also been found satisfactory to produce the necessary and desirable water repellency to the fabric. The application of thesematerials to the fabric is not limited to the use of a dye jig since a padder or any other suitable and convenient type of mpregnating equipment may be used. The material may be applied if desired with a suitable doctor knife equipment. A cellulose derivative-wax composition such as the Other fabrics may be satisfactorily.

Special Tweave following has been found to give satisfactory results:

Percent Cellulose nitrate `3.05 Solvent mixture 55.17 Toluol 28.7 Dibutyl phthalate 6.03 Ceresin wax 4.05 Paramn oil 3.00

The solvent mixture may be: Percent Ethyl acetate 40 Denatured alcohol 60 This composition is preferably applied by means of a suitable doctor knife, the material being applied to both sides of the fabric sumcient penetration being allowed to saturate the material. The volatile solvent is removed by passing the treated material through a heated chamber or over suitably heated coils or in any other manner well known in the art. This treatment imparts excellent Water repellent properties to the fabric material.

In'the cellulose ester composition applied to produce the waterproof and washable lm other White pigments than lithopcne such as titanium oxide, Titanox, zinc oxide and the like may be used with satisfactory results. Colored pigments may be used alone to produce solid vcolors or they may be used with white pigments to produce tints if desired. The choice of the pigmentor pigments used .will depend on the desired color of the waterproof and washable film of the finished product.

Other types of cellulose nitrate than noted in the description ofthe preferred embodiment are l satisfactory. Material having a viscosity characteristic below or above 150 secondsmay be used. The nitrogen content may vary within rather wide limits with'out departing from the spirit of the invention. The choice of the cellulose nitrate to be used may depend on a number of factors and will be readily apparent to those skilled in the art of using such materials.

The solvent or dispersing medium may vary according to practices well known in the art. It is desired to use solvents or dispersing media substantially free from impurities. Other alcohols than ethyl alcohol as methyl, propyl, butyl and the like may be used as well as other esters than ethyl acetate which are commonly known in the art.

The amount of the composition applied to produce the waterproof and washable film may vary over limits and is guidedv largely by the type of finished product desired and general practical and economic considerations. A variation of from 1 to 10 ounces per linear yard 39 inches width finished material has been found to be the most practical although greater or lesser amounts may be used as required.

The lm as deposited on vthe base may or may not be embossed with a suitable design.

It has been generally considered in the art that cellulose nitrate compositions could not be satisfactorily used to produce a waterproof and washable film for adhesive tape or plaster. The usual softened cellulose nitrate compositions have been found to have a deleterious action on the pressure-sensitive adhesive rubber mass commonly used when in contact therewith. The effect is to render the adhesive excessively sticky so as to make it quite difficult or practically impossible t0 unwind from a roll and further to destroy the properties necessary for a satisfactory adhesive. 'I'he material thus becomes unfit for use on even very short storage.

It has been found that vegetable oils, either raw or treated in various ways, stearates of the higher alcohols or ether alcohols and the like when used in conjunction with cellulose nitrate as the softener produce a film which has a deteriorating effect on the pressure-sensitive adhesive rubber mass.

It has also been found in this connection that esters and other derivatives of phthalic acid as benzyl butyl phthalate, diethylene glycol monoethyl ether phthalate, ethylene glycol monoethyl ether phthalate, dicyclohexyl phthalate, glycol isobutyl phthalate, hexahydrobenzyl phthalate, ethylene glycol monomethyl ether phthalate, methyl cyclohexyl phthalate, the phthalates of higher alcohols boiling above 133 deg. C. and a linseed oil modified glycerol phthalate are satisfactory in addition to the dibutyl phthalate noted in the description of a preferred embodiment of the invention and may be used in place thereof. Other materials as dibutyl tartrate, the resinous products obtained from the reaction of glycerols and the poly-glycerols and dibasic acids from the group comprising sebacic, pimelic, suberic, azelaic and adipic acids, acetylated hydrogenated castor oil, phenol formaldehyde resins, aromatic phosphates as tricresyl phosphate, camphor and the like or mixtures thereof, are also satisfactory. In the interest of simplicity, such plasticizers are called rubber adhesive-innocuous plasticizers in the claims, and this term is intended to cover one or a mixture of these plasticizers even though it is used in the singular number. While the percentage of softener in the composition may vary over rather wide limits the preferred range for the most satisfactory results has been found to be between 12 and 19%, with a corresponding pigment range between 1l and 16%. Any variation in percentages of these ingredients may be dictated by practical needs and will be readily apparent to those skilled in the art.

It has been found particularly advantageous to use materials in the film forming composition as free from impurities as practical. For example, it is preferred to use so-ealled virgin cellulose nitrate, solvents or dispersing media which have not previously been used or which have in their rectification been freed from all impurities and good quality pigments. The softeners should also be of the highest order of purity so as to guard against the introduction of any impurities which might have a deleterious action on the adhesive rubber mass.

The product of the invention finds particular use as medical and surgical adhesive tape and plaster particularly where a Waterproof, essentially non-soiling and washable material is desirable or necessary. Because of the desirable properties possessed by the product other uses will readily be suggested to those skilled in the use of such products.

'I'he principal advantage of the invention is the provision of a waterproof adhesive tape or plaster.

Another advantage is the provision of a substantially non-soiling adhesive tape or plaster which can be cleaned by washing if such cleaning becomes necessary.

Another advantage is the provision of a waterproof and cleanable adhesive tape and plaster, the waterproof surface of which does not have a deleterious action on the pressure-sensitive adhesive mass when the two surfaces are in intimate contact with each other and further Whose manufacture and use are commercially and economically practical.

It is apparent that many widely different. embodiments of this invention may be made without departing from the spirit and scope thereof; and, therefore, it is not intended to be limited except as indicated in the appended claims.

We claim:

1. A surgical adhesive tape comprising a fabric base having a pressure-sensitive adhesive containing rubber firmly attached to one side and a coating of a plasticized nitrocellulose composition on the opposite side, the plasticizing component of which consists of a rubber adhesive-innocuous plasticizer, said tape being easily cleanable and highly resistant to water and to soiling.

2. A surgical adhesive tape comprising a cloth base impregnated with a composition which renders it water-repellent and having a pressuresensitive adhesive composition containing rubber on one side and a coating of a composition consisting of nitrocellulose, pigment, and a rubber adhesive-innocuous plasticizer on the other side.

3. Product of claim 2 in which the impregnating composition contains a salt of an acetate of deacetylated chitin, y

4. Product of claim 1 in which the plasticizer .is present in amount between about 12 and 19% of the coating, and a pigment is present in amount between about 11 and 16% of the coating. 5. Process of preparing surgical tape which comprises passing fabric through a bath containing about a 4% emulsion of a wax in an aqueous solution of a salt of an acetate of deacetylated chitin, drying the impregnated fabric, coating one side thereof with a composition which consists of about 72.6 parts of a 24 oz. dispersion of cellulose nitrate, 14 parts of dibutyl phthalate, and 13.4 parts of pigment dispersed in suitable solvents, drying, and thereafter applying a pressure-sensitive adhesive containing rubber to the opposite side of the said fabric.

EDGAR H. NCLLAU. DONALD A. RANKIN. 

